1. Field of the Invention
The present invention relates to an air supply system for vehicles, and more particularly, to an air supply system for a vehicle, which includes a curved diffuser passageway and a volute formed on upper portion of the diffuser passageway to sufficiently secure a length of the diffuser passageway, thereby enhancing a pressure conversion efficiency and reducing a size of the entire system. In addition, the present invention relates to an air supply system for vehicles, which further includes a guide for guiding an air flow toward an input of an impeller, thereby minimizing a loss occurring when air passing through a motor housing flows to the inlet of the impeller, and reducing a weight of an outlet duct.
2. Background Art
In general, vehicles have engines mounted for driving the vehicles, and are divided into gasoline vehicles, diesel vehicles, LPG vehicles, and so on according to kinds of fuel used to the engines. When the vehicle starts, a starting motor is driven by being supplied with electric power from a battery, rotates a flywheel fixed at an end of a crank shaft, and so, the crank shaft is also rotated and a connecting rod connected to the crank shaft performs a reciprocating motion to start the engine.
In the meantime, the diesel vehicle is equipped with an air supply system, which compresses air sucked into an engine and supplies the compressed air to an engine by running a turbine with energy of exhaust gas to thereby enhance output of the engine.
As shown in FIG. 1, the air supply system 1 includes: a turbine part 2 and a compression part 3 mounted integrally on the same axis; a bearing housing 4 located between the turbine part 2 and the compression part 3a; a rotary shaft 5 supported on the bearing housing 4; a turbine wheel 6 of the turbine part 2 mounted on an end portion of the rotary shaft 5; and an impeller 7 of the compression part 3 mounted on the other end portion of the rotary shaft 5. When the exhaust gas discharged from the engine rotates the turbine wheel 6 while passing through the turbine part 2, the impeller 7 of the compression part 3 is simultaneously rotated to compress sucked air, so that the compressed air is supplied into a cylinder of the engine to thereby enhance output of the engine through enhancement of a volume efficiency.
However, in case where the turbine wheel 6 is run by the exhaust gas of the engine, the air supply system 1 generates noise and vibration severely by the pulsation of the exhaust gas of the engine.
In addition, the fuel cell vehicle cannot use the air supply system 1, which uses exhaust gas as energy, as described above since it cannot use exhaust gas. So, the fuel cell vehicle has additional driving motor to operate an air supply system.
For your reference, the fuel cell consists of a number of cells stacked up (called “stack”). The fuel cell is a battery system for generating electricity and heat by progressing electrochemical reaction by electrolysis inverse reaction when fuel (hydrogen gas) and air (oxygen) is supplied to the stack, and so, in fact, may be called “power generating system”.
Here, the air supplied to the stack is supplied through the air supply system 10 operated by the motor. FIG. 2 illustrates an air supply system 10 for such fuel cell vehicles. Now, the air supply system 10 for the fuel cell vehicles will be described in brief. The air supply system 10 includes: a motor part 11 having a rotary shaft 12 mounted at the center thereof and a stator 13 mounted on the periphery of the rotary shaft 12 to rotate the rotary shaft 12; a motor housing 15 accommodating the motor part 11 therein; an impeller 16 coupled to an end portion of the rotary shaft 12 to compress air; a compression housing 17 coupled to the front of the motor housing 15 for accommodating the impeller 16, the compression housing 17 adopted to compress the air sucked through an inlet 17a and discharge the compressed air to a volute 17b when the impeller 16 is rotated; and a bearing housing 18 coupled to the rear of the motor housing 15 for rotatably supporting the other end portion of the rotary shaft 12.
Furthermore, a magnet (not shown) is mounted inside the rotary shaft 12.
So, when the rotary shaft 12 is rotated by running the motor part 11, the impeller 16 mounted inside the compression housing 17 is simultaneously rotated, whereby air is sucked through the inlet 17a of the compression housing 17. The sucked air obtains kinetic energy while passing through the impeller 16, and converts the kinetic energy into pressure while passing through a diffuser passageway 17c of the compression housing 17. The pressure is concentrated on the volute 17b, and in this instance, the inside pressure of the volute 17b increases, and the air having the increased pressure is supplied to the stack.
In the meantime, the compression housing 17 and the bearing housing 18 have ball bearings 14 adapted to rotatably support the rotary shaft 12.
However, in the air supply system 10 according to the prior art, when the diffuser passageway 17c extends in a radial direction to enhance the pressure conversion performance, the entire size of the system is also increased, and the system size is restricted due to the characteristic of parts for vehicles, which have small installation spaces. Finally, the air supply system 10 according to the prior art has a problem in that it cannot secure a sufficient length of the diffuser passageway 17c, and so, is restricted in enhancing the pressure conversion performance.